似士维螨对西洋参根的取食量及其繁殖潜势

【目的】作为西洋参Panax quinquefolium L.的新害虫,似士维螨Schwiebea similis Manson蛀食参根,造成较大的经济损失。本研究旨在测定它对参根的取食量,进而为估算其经济阈值提供参数。【方法】本实验将似士维螨活雌螨接种于含湿沙和西洋参根粉的培养皿中塑料环内,在7级雌螨接种量N_0(每环1,2,3,4,5,6和7♀)和5个温阶T(15.6,18.5,21.2,24.5和27.2℃)条件下培养其实验种群,记载并分析了5类变量:安居期D、峰螨数N_p、雌均殖数PCR、成虫当量AE和均食量FA。【结果】变量D随T升高而快速下降,也因N_0增加而缓慢下降;N_p随N_0增加而显著上升,其回归式为N_p=21.8+17.2N_0;PCR随N_0增加而显著下降,PCR=63.4-28.1N_0+6.2N_0~2-0.4N_0~3,其曲线变化趋势与N_p相反;同时发现了螨虫拥挤效应;AE随N_0增加而显著上升,AE=16.2+12.7N_0;FA=0.25±0.13 mg/头。【结论】这5类变量较为全面地反映了似士维螨实验种群的食量范围和繁殖潜势。上述估算值将为探索其经济阈值提供依据;所用实验方法将为同类研究提供参考。     

土壤中甲螨孳生与铬污染相关性研究

目的 :探讨土壤中甲螨孳生的种群数量与土壤铬污染之间的相互关系。方法 :于某大型化工厂周围土壤 10 m、1km、10 km及远郊农田土壤设立采样点 ,各采集 5 0份样本 ,每份样本采集 (10× 10× 10 )cm3的土壤 ,置 Tullgren电热分螨器中分离甲螨 ,计算甲螨在不同环境中的密度、丰度、优势属 ;同时用原子吸收光谱法分别测定化工厂周围土壤及远郊农田土壤样本中的铬含量。结果 :化工厂周围土壤总体甲螨的密度、丰度和优势度分别为 1975 7(131.71± 2 8.34)个 / m2、131.7个 /样本、嗜草甲螨、门罗点肋甲螨 ,远郊农田土壤甲螨的密度、丰度和优势度分别为 984 5 (6 5 .6 3± 18.36 )个 / m2、6 5 .6 3个 /样本、滑菌甲螨、嗜草甲螨、被盖头甲螨、棒菌甲螨、新小奥甲螨、普通尖棱甲螨 ,两者相比差异有显著性 (P<0 .0 1)。化工厂周围土壤及远郊农田土壤总体铬浓度分别为 (0 .2 5± 0 .0 7) mg/ kg、(0 .0 8± 0 .0 2 ) m g/ kg,两者相比差异有显著性 (P<0 .0 1)。化工厂周围土壤 10 m、1km、10 km、处甲螨的密度分别为 16 4 89(32 9.78± 31.2 2 )个 / m2、2 2 5 7(45 .14± 9.4 5 )个 / m2 、10 11(2 0 .0± 3.33)个 / m2 ,化工厂周围土壤样本的甲螨密度较高 ,与远效农田土壤相比 ,差异有显著性 (P<0 .0 1)。结论     

蔬菜类保健食品"赛金"等对大鼠肠道菌群影响的实验研究

本研究采用人工半合成饲料和代谢实验技术 ,设置对照组 ,观察了我国蔬菜类保健食品“赛金”和典型的茄果类蔬菜 -茄子冷冻干燥粉对生长中大鼠肠道菌群的影响。1　材料与方法1 .1　实验材料　“赛金”为茄子、西红柿等 1 0种新鲜蔬菜冷冻干燥粉的混合物 ,茄子冷冻干燥粉为新鲜茄子冷冻干燥制备而得。均为哈尔滨制药三厂提供。1 .2　动物与分组　选用雄性 Wistar大鼠 2 7只(为二级实验动物 ,购自中国医学科学院实验动物中心 )。平均体重 (60 .1± 1 .5) g,随机分为 3组。于空调动物实验室内、在全塑代谢笼内单独饲养 ,环境参数 :温度 (2 3± …     

反义核酸真核表达载体的构建及其对重组HeLa细胞H654中IVS-2-654C→T突变β-珠蛋白基因剪接缺陷的抑制作用

在原工作的基础上 ,将非细胞系统中证明有效的反义片段通过高效真核表达载体 pCDNA3导入能稳定表达IVS -2 -6 5 4C→T突变 β 珠蛋白基因的重组HeLa细胞 (H6 5 4)中 .结果显示 ,转染后第 3天 ,H6 5 4细胞内正常剪接的β -珠蛋白mRNA水平 ( β/( β + β *) )明显上升 ,从 0 0 7上升到 0 2 2 ,并维持到第 1 5天 ,最高达到0 43.实验表明构建的反义片段真核表达载体在细胞中能稳定转录反义RNA并有效抑制IVS -2 -6 5 4C→T突变β 珠蛋白基因的异常剪接 ,为开展反义核酸治疗剪接缺陷型遗传性疾病提供了更直接的科学依据     

尿螨病的病原学研究

探讨引起尿螨病的病原螨种类,以离心沉淀法浓缩尿液或用铜丝筛（100目／寸）过滤,分离尿液中的螨,直接镜检鉴定螨种,从69例尿螨阳性者的尿液中共分离出17种病原螨,即：粗脚粉螨Acarus siro,腐食酪螨Tyrophagus putrescentiae,长食酪螨T.longior,椭圆食粉螨Aleuroglyphus ovatus,伯氏嗜木螨Caloglyphus berlesei,食菌嗜木螨C.mycophagus,纳氏皱皮螨Suidasianesbitti,河野脂螨Lardoglyphus konoi,家食甜螨Glycyphagus domesticus,甜果螨Carpoglyphuslactis,害嗜鳞螨Lepidoglyphus destructor,粉尘螨Dermatophagoides farinae,屋尘螨D.pteronyssinus,梅氏嗜霉螨Euroglyphus maynei,赫氏蒲螨Pyemotes hughesi,谷跗线螨Tarsonemus granarus,人跗线螨T.hominis,在同一受检者尿液中检出成螨者19例,检出幼螨者18例,同时发现成螨和幼螨者11例,成螨和卵同时检出者3例,成螨,幼螨和卵同时检出者11例,幼螨和卵同时检出者6例,休眠休和卵同时检出者1例;分别占尿螨阳性总数的27．54％,26．09％,15.94%,4.35%,15.94%,8.70%,1.44%.69例悄螨病患者每200mL尿液中检出螨数0．5个以下者32人,0．6－1个者25人,1．1＝－1．5个者10人,1．5个以上者2人,引起尿螨病的病原螨种类较多,其中粉螨是主要的病原螨。     

链霉菌发酵麦草产木聚糖酶的试验研究

通过正交设计试验 ,找出利用链霉菌和麦草基质发酵生产木聚糖酶的试验条件。培养基 (g/L) :麦草粉 ,4 5 ;(NH4 ) 2 SO4 ,7.5 ;酵母膏 ,8;K2 HPO4 ·3H2 O ,1;MgSO4 ·7H2 O ,0 .5 ;NaCl,0 .3。接种量为 5 .0× 10 8个孢子 / 5 0mL培养基 ,振荡培养 (12 0r/min) 5d     

江西真长须螨属记述(蜱螨亚纲:长须螨科)(英)

本文描述了采自江西的5种真长须螨并列出检索表,其中包括3新种:江西真长须螨Eustigmaeus jiangxiensis Hu, Chen and Huang, sp. nov. ;牯岭真长须螨E. gulingensis Hu and Chen, sp. nov. ;龙氏真长须螨E. longi Hu and Chen, sp. nov. 和1中国新纪录种,塞氏真长须螨E. segnis(Koch)。     

Progress in the complete mitochondrial genomes of the Acari

蜱螨亚纲包括蜱类和螨类,是节肢动物中物种多样性最高的类群之一.本文综述了当前已测序的28种蜱螨线粒体基因组的研究成果.概括起来,蜱螨线粒体基因组具有以下特点:(1)大小变异显著,其中柑橘全爪螨Panonychus citri线粒体基因组在目前已测节肢动物中最小(13077 bp);(2)一般碱基组成偏向A和T,但6种蜱螨具有相反的GC-偏斜(正值);(3)基因组的碱基组成及A+T富集区的位置、长度和拷贝数等变异显著,其中4种叶螨的A+T含量最高,其A+T富集区在目前已测节肢动物中最短(44 -57 bp);(4)基因高度重排,特别是真螨总目的种类,但重排与高分类阶元无相关性;(5)真螨总目部分螨类的tRNA基因极度缩短,不能形成经典的三叶草二级结构.作者建议要进一步测定更多蜱螨的线粒体基因组,验证蜱螨非典型tRNA基因的生物学功能性,分析蜱螨线粒体基因组的分子进化机制,开展蜱螨线粒体转录组研究等.     

影响灰褐链霉菌S1001产碱性几丁质酶的因素

河南农业大学筛选的灰褐链霉菌Ｓ1 0 0 1所产碱性几丁质酶 ,经大田实验对Ｂｔ增效明显 ,但菌株产酶量低。本实验旨在探讨影响灰褐链霉菌Ｓ1 0 0 1产碱性几丁质酶量的因素。通过摇瓶发酵 ,用测菌丝干重法 ,得出了产碱性几丁质酶的灰褐链霉菌Ｓ1 0 0 1的营养生长曲线 ,确定了其对数生长期为培养开始后 2 4～ 34ｈ ;对其营养生长条件进行了优化 ,最佳营养生长条件为 :①培养基 (ｇ/Ｌ) :淀粉 2 0 ,ＫＮＯ31 .0 ,Ｋ2 ＨＰＯ41 .0 ,ＮａＣ1 0 .5 ,ＦｅＳＯ4·7Ｈ2 Ｏ 0 .1 ,ＭｇＳＯ4· 7Ｈ2 Ｏ 0 .5 ,,Ｎａ2 ＣＯ36 .0 (单独灭菌 ) ;②培养温度 …     

朱砂叶螨对甲氰菊酯、阿维菌素,哒螨灵及其混剂抗性遗传力的分析(英文)

采用域性状分析法 ,估算了朱砂叶螨对 5种杀螨剂 (3种单剂和 2种混剂 )的抗性现实遗传力 ,并对 5种药剂的抗性风险进行了评估。把采自重庆北碚田间的朱砂叶螨种群 ,在室内不施药情况下饲养 6 0余代 ,以此作为抗性筛选的敏感品系。分别单一连续汰选近 30代 ,朱砂叶螨对甲氰菊酯、阿维菌素、哒螨灵、哒螨 -阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)和甲氰 -阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m)的抗性分别达 6 5 5 5、5 82、1 2 3、5 2 0和 1 4 2 倍 ;抗性现实遗传力分别为 0 2 16 7、0 0 96 7、0 0 130、0 0 80 0和 0 0 172。在实验室选择条件下 ,预计抗性增长 10倍时 ,甲氰菊酯、阿维菌素、哒螨灵、哒螨 -阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)和甲氰 -阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m)分别需要 15、34、333、4 2和 2 0 0代。甲氰菊酯抗性风险较高 ,其次是阿维菌素、哒螨 -阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)、甲氰 阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m) ,哒螨灵抗性风险较低。混剂哒螨 阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)不能延缓朱砂叶螨对两单剂哒螨灵和阿维菌素的抗性发展 ,而混剂甲氰 阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m)却能有效延缓朱砂叶螨对两单剂     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.